Renewable energy from biomass has the potential to reduce dependency on fossil fuels and the corresponding negative environmental impact. Realization of this potential will require the development of high yielding biomass production systems. A major advantage for utilizing tobacco as an energy biomass feedstock is that it is a well established non-food industrial crop that is cultivated in more than 100 countries around the world. When grown for energy production rather than smoking, tobacco biomass can be generated more efficiently and inexpensively than almost any other agricultural crop. In addition, tobacco can be grown on land not involved in food production, such that its production for energy biomass is not replacing growth of a food crop. Further, use of tobacco as a renewable resource as energy biomass promotes energy independence.
As a biomass for cellulosic ethanol fermentation, tobacco has two main advantages over existing feedstocks: a high amount of easily fermentable sugars, and a low content of lignin, which in other lignocellulitic feedstock significantly hampers the fermentation process and contributes to high costs. Tobacco biomass is naturally rich in sugars and starch and low-lignin cellulose. While there is wide variation among tobacco types, generally tobacco contains 15-20% sugars, 8-14% starch and 30-40% cellulose per dry weight.
However, and in contrast to the kernel of corn plants, a major disadvantage to use of tobacco for ethanol fermentation is that the sugar in tobacco is not largely localized in a tissue that can be easily fermented to produce ethanol. An additional disadvantage is that tobacco biomass contains levels of nicotine that can be toxic to certain organisms such as the microbial strains used in the fermentation reaction.
Thus, an unmet need remains for improved compositions and methods for production of ethanol from fermentation of tobacco biomass. The present disclosure provides such improved compositions and methods.